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Cosmology

Since its discovery by A. Linde and others, cosmic inflation -- exponential expansion of the universe driven by the potential energy contained in an `inflaton' field -- has become a successful paradigm of early universe cosmology and the origin of structure in the universe. At the same time, it leads to great theoretical problems which remain unsolved. This is a paradigm in search of a theory, and SITP members (including Dimopoulos, Kachru, Kallosh, Linde, Senatore, and Silverstein) have led a major upgrade of our understanding of the dynamics of inflation, taking into account the sensitivity of inflationary theory to quantum gravity that follows from the enormous expansion of the universe and range of the inflaton field during the process. At the same time, SITP theorists discovered an elegant characterization of observables that are captured by low energy quantum fields, and determined precisely how they are constrained by possible symmetries of nature, including a special candidate known as supersymmetry. . . . (read more)

Video Brief

None of us were consulted when the universe was created. And yet it is tempting to ask not only how the universe evolves, but also why, and could it be different? Our universe weighs more than 1050 tons. Could it be created “on the cheap”? Would it require a comprehensive project plan, and if so, where was this plan written before the universe was born? Can we study the evolution of the universe by cosmological observations, and then “play the movie back” to the origin of time, or will something unavoidably prevent us from doing it? Why do we live in a 4-dimensional space-time?

In the last few decades, we have been able to look at the sky with unprecedented precision and our understanding of the evolution of the universe has changed radically. We have found that the universe is very large and remarkably homogeneous, but at the same time it has structures on all length scales. In order to obtain a universe such as the one we see around us, a quite mysterious period of exponential expansion, called inflation, seems to be required at the beginning of the universe. The universe is also accelerating today, apparently dominated by a cosmological constant.

In the last few decades, we have been able to look at the sky with unprecedented precision and our understanding of the evolution of the universe has changed radically. We have found that the universe is very large and remarkably homogeneous, but at the same time it has structures on all length scales. In order to obtain a universe such as the one we see around us, a quite mysterious period of exponential expansion, called inflation, seems to be required at the beginning of the universe. The universe is also accelerating today, apparently dominated by a cosmological constant.

Cosmological observations show that the universe is very uniform on the maximally large scale accessible to our telescopes. The best theoretical explanation of this uniformity is provided by the inflationary theory. Andrei Linde will briefly describe the status of this theory in view of recent observational data obtained by the Planck satellite. Rather paradoxically, this theory predicts that on a very large scale, much greater than what we can see now, the world may look totally different.

The 8th Asian Winter School on Strings, Particles and Cosmology is part of a series that is being organized annually in turn by Korea, Japan, China and India. The school will be held in Puri, India, as a program of the International Center For Theoretical Sciences, TIFR.